lib/msun/src/w_powf.c

   1 /* w_powf.c -- float version of w_pow.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  *
   4  * $FreeBSD: src/lib/msun/src/w_powf.c,v 1.5 1999/08/28 00:07:07 peter Exp $
   5  * $DragonFly: src/lib/msun/src/Attic/w_powf.c,v 1.2 2003/06/17 04:26:53 dillon Exp $
   6  */
   7
   8 /*
   9  * ====================================================
  10  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  11  *
  12  * Developed at SunPro, a Sun Microsystems, Inc. business.
  13  * Permission to use, copy, modify, and distribute this
  14  * software is freely granted, provided that this notice
  15  * is preserved.
  16  * ====================================================
  17  */
  18
  19 /*
  20  * wrapper powf(x,y) return x**y
  21  */
  22
  23 #include "math.h"
  24 #include "math_private.h"
  25
  26
  27 #ifdef __STDC__
  28         float powf(float x, float y)    /* wrapper powf */
  29 #else
  30         float powf(x,y)                 /* wrapper powf */
  31         float x,y;
  32 #endif
  33 {
  34 #ifdef _IEEE_LIBM
  35         return  __ieee754_powf(x,y);
  36 #else
  37         float z;
  38         z=__ieee754_powf(x,y);
  39         if(_LIB_VERSION == _IEEE_|| isnanf(y)) return z;
  40         if(isnanf(x)) {
  41             if(y==(float)0.0)
  42                 /* powf(NaN,0.0) */
  43                 return (float)__kernel_standard((double)x,(double)y,142);
  44             else
  45                 return z;
  46         }
  47         if(x==(float)0.0){
  48             if(y==(float)0.0)
  49                 /* powf(0.0,0.0) */
  50                 return (float)__kernel_standard((double)x,(double)y,120);
  51             if(finitef(y)&&y<(float)0.0)
  52                 /* powf(0.0,negative) */
  53                 return (float)__kernel_standard((double)x,(double)y,123);
  54             return z;
  55         }
  56         if(!finitef(z)) {
  57             if(finitef(x)&&finitef(y)) {
  58                 if(isnanf(z))
  59                     /* powf neg**non-int */
  60                     return (float)__kernel_standard((double)x,(double)y,124);
  61                 else
  62                     /* powf overflow */
  63                     return (float)__kernel_standard((double)x,(double)y,121);
  64             }
  65         }
  66         if(z==(float)0.0&&finitef(x)&&finitef(y))
  67             /* powf underflow */
  68             return (float)__kernel_standard((double)x,(double)y,122);
  69         return z;
  70 #endif
  71 }